Circuit breaker



J. G. JACKSON CIRCUIT BREAKER Filed Nov. 20, 1940 Aug. 31, 1943.

2 Sheets-Sheet 1 n 0 l7 'iJa Z ATT EY cooperating clamping nut Patented Aug. 31, 1943 UNITED STATES PATENT OFFICE.

CIRCUIT BREAKER John G. Jackson, Detroit, Mich. assignor to Square D Company, Detroit, Mich., a corporation of Michigan Application November 20, 1940, Serial No. 366,362

' 7 Claims. (01. 200-116) Another object of the invention is to provide. in an electric circuit breaker improved arc in- 1 terruption means.

, Another object of the invention is" the provision of an arc chamber having a plurality of bathing means having restricted openings through which the contact operating means extends.

in an electric circuit breaker of a barrier movthe base I in spaced apart parallel arrangement and separate the arc chamber from the circuit breaker mechanism and provide extensive cooling surfaces for any are gases formed upon contact separation to hasten arc interruption.

'- Aligned elongated slots I! extend through the barrier walls H, [5 and IE to receive a flat contact bar l8 which extends through the slots into the arcing chamber and there carries a movable contact surface I9. The barrier wall l2 at the end is provided with an opening 2| to facilitate the escape of arc gases to the exterior. A movable fiber member 22 is disposed between barrier able with the contact operating means which closes the opening in a baffle plate through which the operating means extends.

Other objects and features of the invention will be readily apparent to those skilled in the art from the following specification and appended drawings illustrating certain preferred embodiments of the invention in which:

Figure 1 is a front elevational view of a circuit breaker according to the present invention with the cover removed to show internal parts.

' Figure 2 is a sectional view on the line 11-11 of Figure 1.

Figure 3 is a vertical sectional view of the circuit breaker shown in Figure 1.

The circuit breaker illustrated herein comprises a generally cup-shaped insulating base i having a metallic cover 2 preferably sealably attached thereto by means of spun over portions of. rivets or in any other manner and with an insulating sheet 3 01 fiber or other material disposed in back of the metallic cover 2. Upon an end ledge 4 at the top of the circuit breaker is' mounted a connector 5 asby means of a spun over portion of a metallic insert 6. Secured to the connector 5 is a terminal connector 8 and its 9. The connector 5 extends into the interior of the breaker and there carries a stationary contact surface H. The top portion of the base is sealed off by means of an insulating barrier wall i2 of fiber or other material and the arc chamber surrounding the contact H is provided with fiber liners IS. A plurality of barrier walls formed by insulating fiber sheets l4, l5, and 16 are disposed within walls 15 and I6 and is slotted to receive and fit tightly about the contact bar 18 but be slidable therealong and movable therewith. The member 22 serves to seal the arc chamber upon the occurrence of an arc therein for the pressure of the arc gases generated by an are drawn upon separation of the contacts is sufficient to force the member 22 along the contact bar l8 and against the barrier wall IE to close slot ll sufficiently to prevent any flashover of the are therethrough.

A magnetic yoke is provided for increasing the blowout efiect of the arc gases. This yoke embraces the arc chamber in the area of the cooperating contacts and includes side plates 20 and a bight or connecting portion 30, the side plates 20 being disposed between the fiber liner walls i3 of the arc chamber and the exterior walls of the base I. An additional fiber barrier wall I0 is provided beneath the connector 5 to further aid in the proper directional flow of the arc gases.

The front edge of the bar i8 is provided with a notch 23 'interengaged with the forward end of a slot within the longer leg of a U-shaped member 24 guided for rectilinear movement at right angles to the back of the base by formations within the base. The shorter leg of the U- 24 as shown comprises a stop for the blade in its automatically operated position. At the bottom end of the circuit breaker upon a ledge 25 is mounted a connector 26 as by means of a spun over portion of a metallic insert and having a stud, socket and nut arrangement similar to that at the top of the breaker to provide for terminal connection. The connector 26 extends within the interior of the breaker and at its interior end is adjustably secured 2. current responsive bimetallic strip 28. An insulating wall 32 serves to seal off the bottom of the breaker from the exterior. Upon a shaft 33 received within notches in the side walls of the base is mounted a rotary handle 34 having an interior camming surface adapted to cooperate with the front surface of the rectilinearly movable member 24 and including a stable manual Off surface 35 and a resetting tip 36. A light spring 3! biases the handle for rotation in a clockwise direction as shown. The bimetallic member 29 and the contact bar l8 are electrically connected by means of a flexible lead 38. The end of the bar [8 remote from contact [9 is provided with a latching surface adapted to engage the free end of the bimetallic element 28. A compression spring 4! biases the bar I8 against the stationary contact surface H and against the free end of the bimetallic member 28 and also biases the bar for rotation about its pivotal engagement with the member 24.

The operation of the circuit breaker will now be described. The circuit breaker as shown in Figure 3 is in its normal or closed circuit position. To place the parts in manual off position, the handle 34 is rotated in a clockwise direction until surface 35 thereon engages the top surface of the rectilinearly movable member 24 which by this movement has been moved toward the bottom of the base. In this movement of the member 24 the bar l8 pivots about its latching en gagement with the bimetallic member 28 and moves the contact surface I!) to a position separated from the stationary contact surface I I. To again place the parts in closed circuit position, the handle is rotated in a counterclockwise direction. Upon the occurrence of an overload through the bimetallic element 28, it will become heated to warp toward the end of the base, thereby unlatching its corresponding end of the contact member [8 which will be rotated in a clockwise direction under the bias of the compression spring 4| about the pivotal engagement of the notch 23 with the front edge of the slot in the longer leg of the rectilinearly movable member 24, thus moving the contact surface on the contact member away from its cooperating contact surface H and opening the circuit therethrough. This rotation of the contact member It! will be limited by the engagement of the shorter leg of the U-shaped member 24 with the front edge of the contact member.

The are chamber arrangement herein provided eiTectually seals the main body of the breaker in i which the actuating mechanism is disposed from arc gases generated in the chamber surrounding the contacts. This arcing chamber is of fiber arc resisting material and the arc gases generated therein are eventually evacuated throu h the opening 2|. The bafiie plates l4, l5 and IS with their restricted openings I! through which the bar l8 extends in themselves serve to cool the arc gases and impede theirprogress. It is readily understood that with this series of baflle plates and the restricted openings therein, the gas pressure adjacent the last bailie will be relatively small in view of the successionof small openings in the bafile plates and the relatively large space within the plates in which gases which have passed through the openings can expand. The plurality of plates with the restricted opening causing alternate compression and expansion of gases passing through the baffle plates in and of itself acts to inhibit the passage of gases therethro-ugh and so functions even without the movable insulating plate 22. Further the gases in their passage through the restricted openings will be cooled so that the gases adjacent the barrier 16 will be at low temperature as well as low pressure. However, in the extreme Lil cases where gases adjacent the bame I6 would be at considerable pressure, the plate 22 serves to effectively close the opening I1 in the plate I5 and hence even if the arc gases which have passed through the baffle plates l4 and I5 and have a material pressure, these gases will be prevented from passing into the space occupied by the actuating mechanism by the closure of the slot in the bailie plate 16 by the insulating plate 22 being pressed thereagainst. The resulting structure effectively isolates the actuating mechanism from the arc gases and provides an efficient arc suppressing chamber in which the arc drawn between N the contacts is ruptured.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In a circuit controlling device, a stationary contact, a movable contact, means carrying said movable contact into and out of engagement with the stationary contact, actuating means for eifecting operation of said movable contact carrying means, an insulating barrier disposed between said contacts and said actuating means and having a slot therein through which said movable contact carrying means extends and closely receiving said contact carrying means, and an insulating member mounted on said movable contact carrying means so as to be movable therewith to be positioned in front of the slot in said insulating barrier, said insulating member being movable relative to said movable contact carrying means and toward said insulating barrier by the pressure of are formed gases to close said slot when said movable contact carrying member is in contacts separated position.

2. In an automatic electric circuit breaker, a stationary contact, a movable contact, means including electroresponsive means for eilecting movement of said movable contact to open circuit position in response to predetermined conditions, a plurality of insulating sheets disposed between said contacts and said contact moving means and having openings therein through which extends means carrying the movable contact, and an insulating member movable'relative to said insulating sheets in a first direction with said movable contact carrying means for pcsitioning thereof in alignment with said openings, said member moving relative to said movable contact carrying means in a direction substantially normal to said first direction and into juxtaposition with one of said insulating sheets under the pressure of arc gases generated by said arc to close the opening therein provided for the movable contact carrying means.

3. An electric circuit breaker comprising stationary and movable contacts, operating means for effecting separation of said contacts, a plurality of spaced insulating plates mounted between said contacts and said operating means and having openings therein through which extends means carrying the movable contact, and a movable insulating member disposed between a pair of said spaced insulating plates and movable with the movable contact carrying means for positioning thereof in alignment with said openings. said insulating member being movable relative to said movable contact carrying means and against one of said' insulating plates by the pressure of arc gases generated upon separation of the contacts to close the opening therein and seal oiT said contacts from the actuating means.

4. In an electric circuit breaker, a stationary contact, a movable contact, actuating means for moving said movable contact into and out of engagement with said stationary contact, means to seal off said contacts from said actuating means comprising a pair of cooperating insulating members disposed between said contacts and said actuating means, one of said insulating members being stationary and having a slot therein closely receiving means carrying the movable contact, the other of said insulating members being movable with the movable contact carrying means for positioning thereof in alignment with said slot, said movable insulating member being movable relative to said movable contact carrying means along a longitudinal edge thereof and against the stationary insulating member under the pressure of gases generated by an are drawn actuable to move said movable contacts into and out of engagement with said stationary contact manual and automatic means for actuating saio movable element, an insulating member separating said contacts from said actuating means and having an opening therein closely receiving said 'movable element and a second insulating member embracing said movable element and being movable relative thereto and along an edge thereof under the pressure of arc gases, said movable insulating means cooperating with said insulating member to seal the opening therein to prevent blowing of said are gases into the space occupied by the actuating means.

6, In an automatic electric circuit breaker, a stationary contact, an extended movable element carrying a contact surface at the end thereof for cooperation with said stationary contact, manual and automatic means for actuating said movable element, a plurality of spaced insulating members having openings therein through which said movable element extends separating said contacts from said actuating means and providing an extensive cooling area to any arc drawn on separation of the contacts, a movable insulating member disposed between two of said spaced insulating barrier members and closely embracing said extended movable element, said movable insulating member being movable in a direction substantially normal to the faces of said insulating barriers and against one of said insulating barrier members under the pressure of the arc gases generated upon separation of the contacts to seal the opening therein to prevent the passage of arc gases therethrough.

7. In an electric circuit breaker, a-stationary contact, a movable contact, a movable switching member for moving said movable contact into and out of engagement with said stationary contact, automatic and manual operating means for actuating said switching member, a plurality of spaced barrier walls disposed between said contacts and said operating means transversely to the path of movement of said switch member and having restricted slots therein receiving said switching member, a movable plate-like insulating member disposed between two of said barrier walls being substantially parallel thereto, and closely embracing said switching member and bemg movable therewith, said insulating member being disposed in front of one of the barrier wall openings when the switching member is in con tact separating position and being movable relative to said switching member and along a longitudinal edge thereof under the pressure of arc gases to close the opening against passage of said arc gases.

JOHN G. JACKSON. 

